<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<input type="button"  value="点击添加"  onclick="addEvent();">
<ul id="city">

</ul>

<script type="text/javascript"  >
  function addEvent() {
    var ul = document.getElementById("city");
    var li = document.createElement("li");
    var input = document.createElement("input");
    input.setAttribute("type", "text");
    input.setAttribute("placeholder", "请输入城市");
    li.appendChild(input);
    ul.appendChild(li);
  }
</script>

</body>
</html>